I seem to recall posting something similar to this topic on here quite recently...
Personally i try to take my talents and push them to their limit. My reason for this? Not exactly to help people to begin with, but the fact that i'm ultimately interested in improving something that i find so interesting. Perhaps, my best talent now, was never a talent before, but i improved myself in the field so much, that it has now become a talent. I'm pretty good at giving advice for my age- which is a result of being a considerably decent, deep, constant philosopher of many topics- ranging from religion, to moral, to different kinds of relationships and more.
Now, using what i've learned from being the amateur philosopher that i am, i give back to the people what i learned from watching and listening to them. From considering the ideas they'd originally placed in my head, and sorting through them to determine which are right, which are wrong, and which are best.
I help people with my developed skills in understanding because i WANT to. Because i have trouble helping myself with what i've learned- and if i can't help someone else- everything i've learned in life is a waste. I also believe, the root of happiness is not in a person, but in people united. People are everywhere, and are always influencing eachother. There are a lot of evil influences in the world- but if i have the ability- why wouldn't i want to be a good influence? Perhaps if i implant the good, right ideas into enough peoples minds- someone will eventually come around and plant them into mine since i so have trouble planting them into my own.
This is just my basic reasoning for why i do the things i do to help people. If you'd like me to give you a more definitive explination- ask a more specific question and i'd be happy to.